I'm still exploring this one - so there is the possibility that I'm heading of in the wrong direction (again)

Both methods seem to rely upon calibre running on a PC and serving the content ? YES
I'm hopping that my low power tablet will allow me to have my power hungry PC switched of for everyday stuff like browsing, email, reading books and general frittering.
And that my Synology NAS can provide any needed content, my calibre library is located on my NAS
I've installed Fbreader on my tablet and its asking for a OPDS catalogue, which can apparently be provided by calibre2opds, which I've installed. Calibre2opds instructions is now telling me that I should 'Ensure metadata in ebook file updated' which is ok if your only got a few books, but I'm now pondering how to do that - got quite a few .mobi files
And that's as far as I've got so far, haven't actually generated anything yet or looked at how or where it should be on the NAS

I'll never make a good geek keep getting tempted away by the sun shine